One vertex per element, one color per generator, with an edge from x to x·s.
(1,2)(3,6)(4,5)(7,8)(9,10)(11,15)(12,16)(13,17)(14,18)(19,22)(20,23)(21,24)(25,26,30,35,31,36,42,49)(27,37,40,48,41,52,45,32)(28,33,44,51,43,50,29,34)(38,47,39,53,54,56,55,46)(9,11,14,21)(10,15,18,24)(12,20,13,19)(16,23,17,22)(25,27)(26,32)(28,38)(29,39)(30,45)(31,41)(33,46)(34,47)(35,52)(36,48)(37,49)(40,42)(43,54)(44,55)(50,53)(51,56)(2,5)(6,8)(9,12,14,13)(10,16,18,17)(11,19,21,20)(15,22,24,23)(25,28)(26,33)(27,38)(29,42)(30,44)(31,43)(32,46)(34,49)(35,51)(36,50)(37,47)(39,40)(41,54)(45,55)(48,53)(52,56)(9,13,14,12)(10,17,18,16)(11,20,21,19)(15,23,24,22)(25,29,31,44)(26,34,36,51)(27,39,41,55)(28,42,43,30)(32,47,48,56)(33,49,50,35)(37,53,52,46)(38,40,54,45)(1,3,4,7)(2,6,5,8)(10,18)(15,24)(16,17)(22,23)(28,43)(29,44)(33,50)(34,51)(38,54)(39,55)(46,53)(47,56)A Cayley diagram is a choice, not a fact about the group. Another drawing of this group — in a book, or on a different generating set — may look nothing like this one.